Converting a string to a date in JavaScript

Question

How can I convert a string to a date in JavaScript?

var st = "date in some format"
var dt = new date();

var dt_st= //st in date format same as dt

Answer 1

The best string format for string parsing is the date ISO format together with the JavaScript Date object constructor.

Examples of ISO format: YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS.

But wait! Just using the "ISO format" doesn't work reliably by itself. String are sometimes parsed as UTC and sometimes as localtime (based on browser vendor and version). The best practice should always be to store dates as UTC and make computations as UTC.

To parse a date as UTC, append a Z - e.g.: new Date('2011-04-11T10:20:30Z').

To display a date in UTC, use .toUTCString(),
to display a date in user's local time, use .toString().

More info on MDN | Date and this answer.

For old Internet Explorer compatibility (IE versions less than 9 do not support ISO format in Date constructor), you should split datetime string representation to it's parts and then you can use constructor using datetime parts, e.g.: new Date('2011', '04' - 1, '11', '11', '51', '00'). Note that the number of the month must be 1 less.

---

Alternate method - use an appropriate library:

You can also take advantage of the library Moment.js that allows parsing date with the specified time zone.

Answer 2

Unfortunately I found out that

var mydate = new Date('2014-04-03');
console.log(mydate.toDateString());

returns "Wed Apr 02 2014". I know it sounds crazy, but it happens for some users.

The bulletproof solution is the following:

var parts ='2014-04-03'.split('-');
// Please pay attention to the month (parts[1]); JavaScript counts months from 0:
// January - 0, February - 1, etc.
var mydate = new Date(parts[0], parts[1] - 1, parts[2]); 
console.log(mydate.toDateString());

Answer 3

var st = "26.04.2013";
var pattern = /(\d{2})\.(\d{2})\.(\d{4})/;
var dt = new Date(st.replace(pattern,'$3-$2-$1'));

And the output will be:

dt => Date {Fri Apr 26 2013}

Answer 4

function stringToDate(_date,_format,_delimiter)
{
            var formatLowerCase=_format.toLowerCase();
            var formatItems=formatLowerCase.split(_delimiter);
            var dateItems=_date.split(_delimiter);
            var monthIndex=formatItems.indexOf("mm");
            var dayIndex=formatItems.indexOf("dd");
            var yearIndex=formatItems.indexOf("yyyy");
            var month=parseInt(dateItems[monthIndex]);
            month-=1;
            var formatedDate = new Date(dateItems[yearIndex],month,dateItems[dayIndex]);
            return formatedDate;
}

stringToDate("17/9/2014","dd/MM/yyyy","/");
stringToDate("9/17/2014","mm/dd/yyyy","/")
stringToDate("9-17-2014","mm-dd-yyyy","-")

Answer 5

moment.js (http://momentjs.com/) is a complete and good package for use dates and supports ISO 8601 strings.

You could add a string date and format.

moment("12-25-1995", "MM-DD-YYYY");

And you could check if a date is valid.

moment("not a real date").isValid(); //Returns false

Some display examples

let dt = moment("02-01-2019", "MM-DD-YYYY");
console.log(dt.fromNow()+' |'+dt.format('LL')) 
// output: "3 months ago | February 1, 2019"

See documentation http://momentjs.com/docs/#/parsing/string-format/

Recommendation: I recommend to use a package for dates that contains a lot of formats because the timezone and format time management is really a big problem, moment js solve a lot of formats. You could parse easily date from a simple string to date but I think that is a hard work to support all formats and variations of dates.

Answer 6

Pass it as an argument to Date():

var st = "date in some format"
var dt = new Date(st);

You can access the date, month, year using, for example: dt.getMonth().

Answer 7

If you can use the terrific moment library (e.g. in an Node.js project) you can easily parse your date using e.g.

var momentDate = moment("2014-09-15 09:00:00");

and can access the JS date object via

momentDate ().toDate();

Answer 8

For those who are looking for a tiny and smart solution:

String.prototype.toDate = function(format)
{
  var normalized      = this.replace(/[^a-zA-Z0-9]/g, '-');
  var normalizedFormat= format.toLowerCase().replace(/[^a-zA-Z0-9]/g, '-');
  var formatItems     = normalizedFormat.split('-');
  var dateItems       = normalized.split('-');

  var monthIndex  = formatItems.indexOf("mm");
  var dayIndex    = formatItems.indexOf("dd");
  var yearIndex   = formatItems.indexOf("yyyy");
  var hourIndex     = formatItems.indexOf("hh");
  var minutesIndex  = formatItems.indexOf("ii");
  var secondsIndex  = formatItems.indexOf("ss");

  var today = new Date();

  var year  = yearIndex>-1  ? dateItems[yearIndex]    : today.getFullYear();
  var month = monthIndex>-1 ? dateItems[monthIndex]-1 : today.getMonth()-1;
  var day   = dayIndex>-1   ? dateItems[dayIndex]     : today.getDate();

  var hour    = hourIndex>-1      ? dateItems[hourIndex]    : today.getHours();
  var minute  = minutesIndex>-1   ? dateItems[minutesIndex] : today.getMinutes();
  var second  = secondsIndex>-1   ? dateItems[secondsIndex] : today.getSeconds();

  return new Date(year,month,day,hour,minute,second);
};

Example:

"22/03/2016 14:03:01".toDate("dd/mm/yyyy hh:ii:ss");
"2016-03-29 18:30:00".toDate("yyyy-mm-dd hh:ii:ss");

Answer 9

Just new Date(st);

Assuming that it's the proper format.

Answer 10

new Date(2000, 10, 1) will give you "Wed Nov 01 2000 00:00:00 GMT+0100 (CET)"

See that 0 for month gives you January

Answer 11

If you want to convert from the format "dd/MM/yyyy". Here is an example:

var pattern = /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/;
var arrayDate = stringDate.match(pattern);
var dt = new Date(arrayDate[3], arrayDate[2] - 1, arrayDate[1]);

This solution works in IE versions less than 9.

Answer 12

Timestamps should be casted to a Number

var ts = '1471793029764';
ts = Number(ts); // cast it to a Number
var date = new Date(ts); // works

var invalidDate = new Date('1471793029764'); // does not work. Invalid Date

Answer 13

Date.parse almost gets you what you want. It chokes on the am/pm part, but with some hacking you can get it to work:

var str = 'Sun Apr 25, 2010 3:30pm',
    timestamp;

timestamp = Date.parse(str.replace(/[ap]m$/i, ''));

if(str.match(/pm$/i) >= 0) {
    timestamp += 12 * 60 * 60 * 1000;
}

Answer 14

Convert to format pt-BR:

    var dateString = "13/10/2014";
    var dataSplit = dateString.split('/');
    var dateConverted;

    if (dataSplit[2].split(" ").length > 1) {

        var hora = dataSplit[2].split(" ")[1].split(':');
        dataSplit[2] = dataSplit[2].split(" ")[0];
        dateConverted = new Date(dataSplit[2], dataSplit[1]-1, dataSplit[0], hora[0], hora[1]);

    } else {
        dateConverted = new Date(dataSplit[2], dataSplit[1] - 1, dataSplit[0]);
    }

I hope help somebody!!!

Answer 15

For сonverting string to date in js i use http://momentjs.com/

moment().format('MMMM Do YYYY, h:mm:ss a'); // August 16th 2015, 4:17:24 pm
moment().format('dddd');                    // Sunday
moment().format("MMM Do YY");               // Aug 16th 15
moment().format('YYYY [escaped] YYYY');     // 2015 escaped 2015
moment("20111031", "YYYYMMDD").fromNow(); // 4 years ago
moment("20120620", "YYYYMMDD").fromNow(); // 3 years ago
moment().startOf('day').fromNow();        // 16 hours ago
moment().endOf('day').fromNow();          // in 8 hours

Answer 16

I have created a fiddle for this, you can use toDate() function on any date string and provide the date format. This will return you a Date object. https://jsfiddle.net/Sushil231088/q56yd0rp/

"17/9/2014".toDate("dd/MM/yyyy", "/")

Answer 17

This answer is based on Kassem's answer but it also handles two-digit years. I submitted an edit to Kassem's answer, but in case it wasn't approved, I'm also submitting this as a separate answer.

function stringToDate(_date,_format,_delimiter) {
        var formatLowerCase=_format.toLowerCase();
        var formatItems=formatLowerCase.split(_delimiter);
        var dateItems=_date.split(_delimiter);
        var monthIndex=formatItems.indexOf("mm");
        var dayIndex=formatItems.indexOf("dd");
        var yearIndex=formatItems.indexOf("yyyy");
        var year = parseInt(dateItems[yearIndex]); 
        // adjust for 2 digit year
        if (year < 100) { year += 2000; }
        var month=parseInt(dateItems[monthIndex]);
        month-=1;
        var formatedDate = new Date(year,month,dateItems[dayIndex]);
        return formatedDate;
}

stringToDate("17/9/14","dd/MM/yyyy","/");
stringToDate("17/9/2014","dd/MM/yyyy","/");
stringToDate("9/17/2014","mm/dd/yyyy","/")
stringToDate("9-17-2014","mm-dd-yyyy","-")

Answer 18

Performance

Today (2020.05.08) I perform tests for chosen solutions - for two cases: input date is ISO8601 string (Ad,Bd,Cd,Dd,Ed) and input date is timestamp (At, Ct, Dt). Solutions Bd,Cd,Ct not return js Date object as results, but I add them because they can be useful but I not compare them with valid solutions. This results can be useful for massive date parsing.

Conclusions

• Solution new Date (Ad) is 50-100x faster than moment.js (Dd) for all browsers for ISO date and timestamp
• Solution new Date (Ad) is ~10x faster than parseDate (Ed)
• Solution Date.parse(Bd) is fastest if wee need to get timestamp from ISO date on all browsers

Details

I perform test on MacOs High Sierra 10.13.6 on Chrome 81.0, Safari 13.1, Firefox 75.0. Solution parseDate (Ed) use new Date(0) and manually set UTC date components.

let ds = '2020-05-14T00:00Z'; // Valid ISO8601 UTC date
let ts = +'1589328000000';    // timestamp

let Ad = new Date(ds);
let Bd = Date.parse(ds);
let Cd = moment(ds);
let Dd = moment(ds).toDate();
let Ed = parseDate(ds);

let At = new Date(ts);
let Ct = moment(ts);
let Dt = moment(ts).toDate();

log = (n,d) => console.log(`${n}: ${+d} ${d}`);

console.log('from date string:', ds)
log('Ad', Ad);
log('Bd', Bd);
log('Cd', Cd);
log('Dd', Dd);
log('Ed', Ed);
console.log('from timestamp:', ts)
log('At', At);
log('Ct', Ct);
log('Dt', Dt);



function parseDate(dateStr) {
  let [year,month,day] = dateStr.split(' ')[0].split('-');
  let d=new Date(0);
  d.setUTCFullYear(year);
  d.setUTCMonth(month-1);
  d.setUTCDate(day)
  return d;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.19.1/moment-with-locales.min.js"></script>

This snippet only presents used soultions  

Results for chrome

Answer 19

I made this function to convert any Date object to a UTC Date object.

function dateToUTC(date) {
    return new Date(date.getUTCFullYear(), date.getUTCMonth(), date.getUTCDate(), date.getUTCHours(), date.getUTCMinutes(), date.getUTCSeconds());
}


dateToUTC(new Date());

Answer 20

You Can try this:

function formatDate(userDOB) {
  const dob = new Date(userDOB);

  const monthNames = [
    'January', 'February', 'March', 'April', 'May', 'June', 'July',
     'August', 'September', 'October', 'November', 'December'
  ];

  const day = dob.getDate();
  const monthIndex = dob.getMonth();
  const year = dob.getFullYear();

  // return day + ' ' + monthNames[monthIndex] + ' ' + year;
  return `${day} ${monthNames[monthIndex]} ${year}`;
}

console.log(formatDate('1982-08-10'));

Answer 21

Yet another way to do it:

String.prototype.toDate = function(format) {
    format = format || "dmy";
    var separator = this.match(/[^0-9]/)[0];
    var components = this.split(separator);
    var day, month, year;
    for (var key in format) {
        var fmt_value = format[key];
        var value = components[key];
        switch (fmt_value) {
            case "d":
                day = parseInt(value);
                break;
            case "m":
                month = parseInt(value)-1;
                break;
            case "y":
                year = parseInt(value);
        }
    }
    return new Date(year, month, day);
};
a = "3/2/2017";
console.log(a.toDate("dmy"));
// Date 2017-02-03T00:00:00.000Z

Answer 22

var date = new Date(year, month, day);

or

var date = new Date('01/01/1970');

date string in format '01-01-1970' will not work in FireFox, So better use "/" instead of "-" in date format string.

Answer 23

If you need to check the contents of the string before converting to Date format:

// Convert 'M/D/YY' to Date()
mdyToDate = function(mdy) {
  var d = mdy.split(/[\/\-\.]/, 3);

  if (d.length != 3) return null;

  // Check if date is valid
  var mon = parseInt(d[0]), 
      day = parseInt(d[1]),
      year= parseInt(d[2]);
  if (d[2].length == 2) year += 2000;
  if (day <= 31 && mon <= 12 && year >= 2015)
    return new Date(year, mon - 1, day);

  return null; 
}

Answer 24

I have created parseDateTime function to convert the string to date object and it is working in all browser (including IE browser), check if anyone required, reference https://github.com/Umesh-Markande/Parse-String-to-Date-in-all-browser

    function parseDateTime(datetime) {
            var monthNames = [
                "January", "February", "March",
                "April", "May", "June", "July",
                "August", "September", "October",
                "November", "December"
              ];
            if(datetime.split(' ').length == 3){
                var date = datetime.split(' ')[0];
                var time = datetime.split(' ')[1].replace('.00','');
                var timearray = time.split(':');
                var hours = parseInt(time.split(':')[0]);
                var format = datetime.split(' ')[2];
                var bits = date.split(/\D/);
                date = new Date(bits[0], --bits[1], bits[2]); /* if you change format of datetime which is passed to this function, you need to change bits e.x ( bits[0], bits[1], bits[2 ]) position as per date, months and year it represent bits array.*/
                var day = date.getDate();
                var monthIndex = date.getMonth();
                var year = date.getFullYear();
                if ((format === 'PM' || format === 'pm') && hours !== 12) {
                    hours += 12;
                    try{  time = hours+':'+timearray[1]+':'+timearray[2] }catch(e){ time = hours+':'+timearray[1] }
                } 
                var formateddatetime = new Date(monthNames[monthIndex] + ' ' + day + '  ' + year + ' ' + time);
                return formateddatetime;
            }else if(datetime.split(' ').length == 2){
                var date = datetime.split(' ')[0];
                var time = datetime.split(' ')[1];
                var bits = date.split(/\D/);
                var datetimevalue = new Date(bits[0], --bits[1], bits[2]); /* if you change format of datetime which is passed to this function, you need to change bits e.x ( bits[0], bits[1], bits[2 ]) position as per date, months and year it represent bits array.*/
                var day = datetimevalue.getDate();
                var monthIndex = datetimevalue.getMonth();
                var year = datetimevalue.getFullYear();
                var formateddatetime = new Date(monthNames[monthIndex] + ' ' + day + '  ' + year + ' ' + time);
                return formateddatetime;
            }else if(datetime != ''){
                var bits = datetime.split(/\D/);
                var date = new Date(bits[0], --bits[1], bits[2]); /* if you change format of datetime which is passed to this function, you need to change bits e.x ( bits[0], bits[1], bits[2 ]) position as per date, months and year it represent bits array.*/
                return date;
            }
            return datetime;
        }

    var date1 = '2018-05-14 05:04:22 AM';   // yyyy-mm-dd hh:mm:ss A
    var date2 = '2018/05/14 05:04:22 AM';   // yyyy/mm/dd hh:mm:ss A
    var date3 = '2018/05/04';   // yyyy/mm/dd
    var date4 = '2018-05-04';   // yyyy-mm-dd
    var date5 = '2018-05-14 15:04:22';   // yyyy-mm-dd HH:mm:ss
    var date6 = '2018/05/14 14:04:22';   // yyyy/mm/dd HH:mm:ss

    console.log(parseDateTime(date1))
    console.log(parseDateTime(date2))
    console.log(parseDateTime(date3))
    console.log(parseDateTime(date4))
    console.log(parseDateTime(date5))
    console.log(parseDateTime(date6))

**Output---**
Mon May 14 2018 05:04:22 GMT+0530 (India Standard Time)
Mon May 14 2018 05:04:22 GMT+0530 (India Standard Time)
Fri May 04 2018 00:00:00 GMT+0530 (India Standard Time)
Fri May 04 2018 00:00:00 GMT+0530 (India Standard Time)
Mon May 14 2018 15:04:22 GMT+0530 (India Standard Time)
Mon May 14 2018 14:04:22 GMT+0530 (India Standard Time)

Answer 25

You can using regex to parse string to detail time then create date or any return format like :

//example : let dateString = "2018-08-17 01:02:03.4"

function strToDate(dateString){
    let reggie = /(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2}).(\d{1})/
  , [,year, month, day, hours, minutes, seconds, miliseconds] = reggie.exec(dateString)
  , dateObject = new Date(year, month-1, day, hours, minutes, seconds, miliseconds);
  return dateObject;
}
alert(strToDate(dateString));

Answer 26

ISO 8601-esque datestrings, as excellent as the standard is, are still not widely supported.

This is a great resource to figure out which datestring format you should use:

http://dygraphs.com/date-formats.html

Yes, that means that your datestring could be as simple as as opposed to

"2014/10/13 23:57:52" instead of "2014-10-13 23:57:52"

Answer 27

                //little bit of code for Converting dates 

                var dat1 = document.getElementById('inputDate').value;
                var date1 = new Date(dat1)//converts string to date object
                alert(date1);
                var dat2 = document.getElementById('inputFinishDate').value;
                var date2 = new Date(dat2)
                alert(date2);

Answer 28

use this code : (my problem was solved with this code)

function dateDiff(date1, date2){
var diff = {}                           // Initialisation du retour
var tmp = date2 - date1;

tmp = Math.floor(tmp/1000);             // Nombre de secondes entre les 2 dates
diff.sec = tmp % 60;                    // Extraction du nombre de secondes

tmp = Math.floor((tmp-diff.sec)/60);    // Nombre de minutes (partie entière)
diff.min = tmp % 60;                    // Extraction du nombre de minutes

tmp = Math.floor((tmp-diff.min)/60);    // Nombre d'heures (entières)
diff.hour = tmp % 24;                   // Extraction du nombre d'heures

tmp = Math.floor((tmp-diff.hour)/24);   // Nombre de jours restants
diff.day = tmp;

return diff;

}

Answer 29

I wrote a reusable function that i use when i get date strings from the server.
you can pass your desired delimiter( / - etc..) that separates the day month and year in order to use the split() method.
you can see & test it on this working example.

<!DOCTYPE html>
<html>
  <head>
    <style>
    </style>
  </head>
  <body>
    <div>
      <span>day:
      </span> 
      <span id='day'>
      </span>
    </div>
    <div>
      <span>month:
      </span> 
      <span id='month'>
      </span>
    </div>
    <div>
      <span>year:
      </span> 
      <span id='year'>
      </span>
    </div>
    <br/>
    <input type="button" id="" value="convert" onClick="convert('/','28/10/1980')"/>
    <span>28/10/1980
    </span>
    <script>
      function convert(delimiter,dateString)
      {
        var splitted = dateString.split('/');
        // create a new date from the splitted string 
        var myDate = new Date(splitted[2],splitted[1],splitted[0]);
        // now you can access the Date and use its methods 
        document.getElementById('day').innerHTML = myDate.getDate();
        document.getElementById('month').innerHTML = myDate.getMonth();
        document.getElementById('year').innerHTML = myDate.getFullYear();
      }
    </script>
  </body>
</html>

Answer 30

Yet another way to do it is to build a regex with named capture groups over the format string and then use that regex to extract the day, month and year from the date string:

function parseDate(dateStr, format) {
  const regex = format.toLocaleLowerCase()
    .replace(/\bd+\b/, '(?<day>\\d+)')
    .replace(/\bm+\b/, '(?<month>\\d+)')
    .replace(/\by+\b/, '(?<year>\\d+)')
  
  const parts = new RegExp(regex).exec(dateStr) || {};
  const { year, month, day } = parts.groups || {};
  return parts.length === 4 ? new Date(year, month-1, day) : undefined;
}

const printDate = x => console.log(x ? x.toLocaleDateString() : x);

printDate(parseDate('05/11/1896', 'dd/mm/YYYY'));
printDate(parseDate('07-12-2000', 'dd-mm-yy'));
printDate(parseDate('07:12:2000', 'dd:mm:yy'));
printDate(parseDate('2017/6/3', 'yy/MM/dd'));
printDate(parseDate('2017-6-15', 'y-m-d'));
printDate(parseDate('2015 6 25', 'y m d'));
printDate(parseDate('2015625', 'y m d')); // bad format